The present invention relates to a novel process for producing IC card.
As the process for producing IC card, the following methods are heretofore known:
(a) a heat laminate molding method, (b) a resin filling method, (c) an injection molding method, and
(d) an adhesion method with a hot melt resin. However, these methods have the following drawbacks.
The method (a) has a problem that a production process is complicated, and production cost increases because the recesses must be formed on the resinous base in compliance with the various shapes of individual IC module which is embedded in said recesses (see, for example, Japanese Patent Publications (KOKAI) No. 109693/1987 and No. 300868/1997).
The method (b) has not only a drawback that at least one side of the card must be transparent (UV curable resins) or setting time is so long that a workability is low (thermoset resins) but also a problem that an additional process is necessary in order to arrange a spacer.
The method (c) has a problem that not only a production efficiency is low as two injection processes are necessary but also a yield of the card is low because of the breakdown of IC module and a crook of the card caused by high temperature and pressure at the time of injection molding (see, for example, Japanese Patent Publication (KOKAI) No. 24000/1991).
The method (d) has not only a drawback that hot melt resins having high softening temperature cannot be applied to plastic base materials having low heat resistance or hot melt resins having low softening temperature lower a heat resistance of the card but also a problem that when the laminate sheet consisting of a top sheet, a base sheet, and an interlayer sheet carrying IC module which is lain between the top sheet and the base sheet is subjected to a contact bonding process with reactive curing hot melt resins under normal pressure, a quality of the IC card is lowered owing to blisters formed within the laminate sheet, said blisters being attributable to a concentration of carbon dioxide produced during the reaction in air bubbles within the laminate sheet. For example, appearance and printability (surface smoothness) are deteriorated owing to the concave and convex parts formed on the surface of the IC card, and strength, heat resistance, chemical resistance, water resistance and the like are lowered owing to the deterioration of gastightness of the IC card (see, for example, Japanese Patent Publications(KOKAI) No.270173/1993 and No. 147087/1998).
The present invention has been carried out to provide inexpensively IC card having high commodity value and great expectations of various uses by solving the aforesaid problems concerning the former methods of producing the IC card.
The present invention relates to a process for producing IC card consisting of a top sheet, a base sheet, and an interlayer sheet carrying IC module, said interlayer sheet being lain between said top sheet and base sheet, and said IC module being laid on or embedded in said interlayer sheet, characterized in that said top, base and interlayer sheets are subjected to a contact bonding process with a reactive polyurethane hot melt resin under reduced pressure.